Cervical length in the early second trimester for detection of triplet pregnancies at risk for preterm birth

Objective. Preterm triplet delivery is common and has a tremendous impact on neonatal mortality and morbidity. We aimed at assessing early second-trimester cervical length as a means of detecting triplet pregnancies at risk for preterm birth. Methods. Cervical length was measured in triplet pregnancies during weeks 14 to 20. Cervical length of less than 25 mm was used as a cutoff to divide individuals into 2 groups. Perinatal outcome parameters were compared between the 2 groups and included gestational age at delivery, birth weights, and neonatal intensive care unit admission rates. Sensitivity, specificity, and positive and negative predictive values were calculated for cervical length as a screening method for preterm birth. Results. We evaluated 36 triplets during weeks 14 to 20. Cervical length of less than 25 mm was measured in 14 (group I), 12 of which were delivered before 32 weeks (mean ± SD, 28.4 ± 3.1 weeks). Four of 22 women with cervical length of greater than 25 mm (group II) had delivery before 32 weeks (mean, 30.1 ± 1.8 weeks). The mean gestational age at delivery for all parturients from group II was 33.1 ± 2.1 weeks (P < .05). Group I neonates had lower birth weights (972 versus 1889 g; P < .001) and higher rates of low 5-minute Apgar scores and neonatal intensive care unit admissions compared with group II neonates. The sensitivity of a shorter cervix as a predictor of preterm labor was 75%, with specificity of 90%, a positive predictive value of 83%, and a negative predictive value of 81%. Conclusions. Cervical length of less than 25 mm at 14 to 20 weeks' gestation is associated with preterm delivery and adverse perinatal outcome in triplet pregnancies.